1. Field of the Invention
The present invention relates to a wafer structure, and more particularly, to a wafer structure in which a mirror shot is performed for a partial area of a wafer for stable die attachment.
2. Description of the Related Art
For semiconductor circuit devices that are assembled after a test is completed, a good die and a bad die are accurately classified only by recognition of the presence of inking, and die attachment is performed only for the good die. The inking is performed to classify a good die and a bad die by marking a surface of each die using ink. As wafer sizes increase and become thin, inking is omitted and accordingly a probability of generation of defects during the die attachment operation increases.
When die attachment is performed by configuring a wafer map with a full shot without inking, a first die is recognized and a good die is selected based on the recognized first die so that the die attachment is performed. That is, instead of inking, the first die that works as a reference coordinate is recognized, and the good die and the bad die are searched to use its coordinate to perform the die attachment operation.
However, since there is no specific reference in recognition of the first die, an error can occur in the coordinate of the first die so that the good die attachment performed based on the first die coordinate may be defective. That is, instead of the good die, the bad die can be attached. Thus, a method for accurately recognizing the position of the first die is needed for the good die attachment.